For live the formula is some thing like this -25% if i need to give 25% discount on each product in my cart3. Setup the CAT_Card module to use Advanced Coupons:Select ‘View Options’ from the module menu of module CAT_Cart and turn on the option: ‘Use advanced coupon management’

The same coupon code can be used only once by a customer but multiple times by different customers.Fixed coupon amounts are partial redeemable. The balances will be displayed in the cart module.If a customer removes a Coupon Code from the cart it can be reused

Note: After Coupon code activation you must uncheck the "turn off the Indvidual items option in the paypal" under store settings

If you can't do that step this error arrives on the paypal"The linkyou have used to enter the paypal system contains an Incorrectly formatted item amount"